Biofiltration of high concentration of H2S in waste air under extreme acidic conditions.

Removal of high concentrations of hydrogen sulfide using a biofilter packed with expanded schist under extreme acidic conditions was performed. The impact of various parameters such as H2S concentration, pH changes and sulfate accumulation on the performances of the process was evaluated. Elimination efficiency decreased when the pH was lower than 1 and the sulfate accumulation was more than 12 mg S-SO4(2-)/g dry media, due to a continuous overloading by high H2S concentrations.